Lawesson's reagent (LR) is a chemical compound used in organic synthesis as a thiation agent.

Samples give a strong odor of hydrogen sulfide owing to partial hydrolysis.

One common and effective method of destroying the foul smelling residues is to use an excess of sodium hypochlorite (chlorine bleach).

[7] Additionally, Lawesson's reagent has been used to thionate enones, esters,[8] lactones,[9] amides, lactams,[10] and quinones.

[11] A combination of silver perchlorate and Lawesson's reagent is able to act as an oxophilic Lewis acid with the ability to catalyze the Diels–Alder reaction of dienes with α,β-unsaturated aldehydes.